It is well known that many vehicles, including motorcycles, snowmobiles, all-terrain vehicles, watercraft, and the like, are powered by internal combustion engines. Typically, these engines are positioned within engine compartments and are adapted to propel the vehicles. Generally, each internal combustion engine has one or more cylinders (i.e., combustion chambers) each communicating with an air intake and a fuel supply. The engine generates power in each cylinder by combusting a mixture comprising air supplied from the air intake and fuel from the fuel supply. Typically, the air supplied to the air intake is obtained from the ambient air surrounding the vehicle. However, as is well known, it is undesirable to allow contaminants from the air, such as water, dirt, and the like, to enter the air intake of such an engine, as the contaminants may plug the air intake. Alternatively, if the contaminants pass through the air intake and enter the cylinder(s), the engine could likely stall or stop. In addition, if the contaminants pass through the air intake, they could seriously damage the engine. For example, if water enters one of the cylinders, it can remove lubrication from the cylinder wall, causing piston seizure. Additionally, if water enters the engine crankcase, it can cause corrosion of the crankcase and needle bearings.
The vehicles mentioned above generally have one or more openings in their engine compartments that enable the entry of the ambient air into the air intake. For example, on a snowmobile, it is most common to find these vent openings near the operator of the vehicle, generally in the snowmobile console. One advantage of positioning the openings in this location is that airborne contaminants are less likely to fly into the openings from the rear side of the body assembly. In turn, there would be less chance for these contaminants to either plug the air intake or pass through the air intake and damage the engine. However, one disadvantage of positioning the vent openings in this location is that noise from the engine generally travels back through the air intake and out the openings, thereby creating a nuisance for the operator. Another disadvantage is the relative lack of fresh air that enters the air intake from the rear side of the body assembly.
As such, it is desirable to provide an air intake system for vehicles that prevents airborne contaminants from entering the engine through the air intake. Additionally, it would be desirable to prevent the entry of contaminants into the engine while modifying the air intake so that the engine noise traveling back through the air intake to reach the operator may be reduced or even eliminated, and so that fresh air may be received by the air intake.